Metadata Matches Regex

apiVersion: kyverno.io/v1
kind: ClusterPolicy
metadata:
  name: metadata-match-regex
  annotations:
    policies.kyverno.io/title: Metadata Matches Regex
    policies.kyverno.io/category: Other
    policies.kyverno.io/severity: medium
    policies.kyverno.io/subject: Pod, Label
    policies.kyverno.io/description: Rather than a simple check to see if given metadata such as labels and annotations are present, in some cases they need to be present and the values match a specified regular expression. This policy illustrates how to ensure a label with key `corp.org/version` is both present and matches a given regex, in this case ensuring semver is met.
spec:
  validationFailureAction: Audit
  background: false
  rules:
    - name: check-for-regex
      match:
        any:
          - resources:
              kinds:
                - Pod
      validate:
        message: "The label `corp.org/version` is required and must match the specified regex: ^v[0-9].[0-9].[0-9]$"
        deny:
          conditions:
            all:
              - key: "{{ regex_match('^v[0-9].[0-9].[0-9]$','{{request.object.metadata.labels.\"corp.org/version\" || 'empty'}}') }}"
                operator: Equals
                value: false